How is house value calculated come renewal?

Zola.

First time buyer here.....I am due to remortgage soon after a 5 year fix, early next year... since we took the mortgage out we have overpaid consistently and as a result we have taken about 1.5 years off the standard mortgage time.

House prices in our area have definitely gone up, but they are not exactly consistent in price, I would say around 15-20% is the average.

Come renewal, who determines what the house is worth? Does the mortgage lender take the latest average house selling prices in the area to determine this... curious about how this is decided? We bought a house that needed cosmetic work and pumped a fair bit into it which would certainly make it a lot more enticing to buy, but no-one will come to look at this I am sure!.. Is there anything I can do to ensure the house value is captured at its most valuable to help with LTV?

If the average value is now indeed 20% more, then my LTV should be just about in the 60% range, which of course will help with getting a good saving on interest rate...

Novice_investor101

Can't really comment on how they value it, but they do redo it when you renew so they can tell which mortgages you can apply for & at what rates
.
I bought my house for £100k in 2013 & paid a 25% deposit - so 75%LTV.
Come renewal in 2018 it was valued at £135k with my LTV at about 50% so I got the below 65% rates.

Now when I check it online my LTV is about 43% with £52k still owing. I've overpayed a bit but the changes in LTV have mainly come from the house gaining about £40k in value in the last 6 years (I got lucky & by chance bought at the bottom of the last proper crash).